Medical Devices, Systems And Methods Utilizing Permanent Magnet And Magnetizable Feature

ABSTRACT

Systems, methods and devices are described including a catheter adapter subassembly including a magnetic feature. Systems include such a catheter adapter subassembly and a needle subassembly including a magnetic feature, and relative movement of the catheter adapter subassembly and the needle subassembly can be determined using a magnetometer.

FIELD

Principles and embodiments of the present disclosure relate generally todevices, systems and methods including a permanent magnet and amagnetizable feature.

BACKGROUND

Traditionally, penetration of a needle and catheter tubing through skintissue to reach the vein during catheter insertion is invisible toclinicians. For this reason, they must rely on their first-handexperience with needle insertion in combination with tactile sense tosuccessfully identify the location of the vein. This may be a difficulttask when attempting to access a small vein in a deep location under theskin, increasing risk of excess pain and/or injury to the patient.

Emerging procedural guidance systems utilize a combination of ultrasoundand magnetic technologies to provide visualization of subdermal anatomyand device position in the in-plane and out-of-plane orientations. Thiscombination of ultrasound and magnetic methods also allows for theprojection or anticipation of the insertion device position relative tothe patient's anatomy, and thereby improves the likelihood ofsuccessfully accessing the vasculature and completing the invasiveprocedure.

One leading technology targets the cannula as the portion of theinvasive device for magnetization, while another leading technology usesa permanent magnet located on the needle hub of the device. Although apermanent magnet offers a more reliable magnetic field as it is notsubject to the variation of the clinician magnetizing the needle at thepoint of use, it does rely more on a calculated projection of the needletip location. The system that relies on magnetizing the cannula prior toinsertion can more reliably measure the actual tip location, but thismethod is subject to variability on consistently magnetizing the cannulaas it relies on the clinician to place the needle into a magnetic deviceto magnetize the needle. Both of these systems utilize a magnetic fieldgenerated by a portion of the cannula subassembly, and therefore, is notable to measure or predict relative motion between the needle hub andcatheter adapter subassemblies. Understanding the relative position andmotion of these two subassemblies can be used to inform a clinician ofprocedurally important states of the insertion process, such as when theneedle tip reaches the vein, when the catheter tip reaches the vein,when the catheter is advanced to cover the needle tip (“hooding thecatheter”) and thereby safe for further advancement. It would bedesirable to provide medical devices, system and methods that could beused with devices, systems and methods to provide improved visualizationduring penetration of a needle through a patient's skin tissue.

SUMMARY

Various embodiments are listed below. It will be understood that theembodiments listed below may be combined not only as listed below, butin other suitable combinations in accordance with the scope of thedisclosure. A first aspect pertains to a medical device comprising acatheter assembly, the catheter assembly including a catheter adaptersubassembly and a needle subassembly, wherein one of the catheteradapter subassembly and the needle subassembly includes a permanentmagnet element, and the other of the catheter subassembly and the needlesubassembly includes a magnetizable feature.

A second aspect pertains to a system for determining relative positionof a catheter adapter subassembly and a needle subassembly comprising acatheter having a catheter distal tip and a needle having a needledistal tip; a permanent magnet element associated with one of thecatheter adapter subassembly and needle subassembly; a magnetizablefeature associated with the other of the catheter adapter subassemblyand the needle subassembly; and magnetometers positioned with respect tothe catheter adapter subassembly and the needle subassembly, themagnetometers configured to determine relative movement of the catheteradapter subassembly and needle subassembly.

A third aspect pertains to a method for determining a relative positionof a catheter tip and a needle cannula tip, the method comprisingproviding a catheter adapter subassembly including catheter and a needlesubassembly including a needle, the catheter having a catheter distaltip and the needle having a needle distal tip; associating a permanentmagnet element with one of the catheter and the needle; associating amagnetizable feature with the other of the catheter and the needle;obtaining a measured position of the permanent magnet; obtaining ameasured position of the magnetizable feature to obtain a calculatedposition of the catheter distal tip and a calculated position of theneedle distal tip; and comparing the calculated position of the catheterdistal tip with the calculated position of the needle distal tip todetermine the relative position of the catheter distal tip and theneedle distal tip.

A fourth aspect pertains to a catheter adapter subassembly comprising amagnetic feature selected from the group consisting of a metal mandrelfor connecting catheter tubing to the hub, a catheter tubing adhesive, ablood control component of the catheter adapter subassembly, and amagnetic wedge on the catheter adapter body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a catheter assembly that can be utilizedaccording to an embodiment;

FIG. 2 is an exploded perspective view of the catheter assembly shown inFIG. 1;

FIG. 3 is a top plan view of the catheter assembly shown in FIG. 1;

FIG. 4 is a top plan view of a catheter assembly according to anembodiment;

FIG. 5 shows the catheter assembly of FIG. 4 with the needle subassemblyand catheter adapter subassembly separated;

FIG. 6A is a top plan view showing a portion of a needle subassemblywith the needle disconnected from the needle chamber and a magneticfeature;

FIG. 6B is a top plan view showing a portion of an alternativeembodiment of a needle subassembly with the needle disconnected from theneedle chamber and a magnetic feature;

FIG. 6C is a top plan view showing a portion of an alternativeembodiment of a needle subassembly with the needle disconnected from theneedle chamber and a magnetic feature;

FIG. 6D is a top plan view showing a portion of an alternativeembodiment of a needle subassembly with the needle disconnected from theneedle chamber and a magnetic feature;

FIG. 6E is a top plan view showing a portion of an alternativeembodiment of a needle subassembly with the needle disconnected from theneedle chamber and a magnetic feature;

FIG. 7 is a top plan view of an embodiment of a catheter assemblyaccording to an embodiment;

FIG. 8 is a top plan view of an embodiment of a catheter assemblyaccording to an embodiment;

FIG. 9 shows the catheter assembly of FIG. 8 with the needle subassemblyand catheter adapter subassembly separated;

FIG. 10A is a top plan view of a catheter adapter subassembly accordingto an embodiment;

FIG. 10B is a top plan view of a catheter adapter subassembly accordingto an embodiment;

FIG. 10C is a top plan view of a catheter adapter subassembly accordingto an embodiment;

FIG. 10D is a top plan view of a catheter adapter subassembly accordingto an embodiment;

FIG. 11 is a perspective view of a catheter assembly showing optionalfeatures;

FIG. 12A is a top plan view of an embodiment of a catheter assembly;

FIG. 12B shows the catheter assembly of FIG. 12A in a first position;

FIG. 12C shows the catheter assembly of FIG. 12A with the needlesubassembly and catheter adapter subassembly moved with respect to eachother;

FIG. 12C shows the catheter assembly of FIG. 12A with the needlesubassembly and catheter adapter subassembly moved further apart withrespect to each other; and

FIG. 13 shows an embodiment of a system.

DETAILED DESCRIPTION

Before describing several exemplary embodiments, it is to be understoodthat the disclosure is not limited to the details of construction orprocess steps set forth in the following description. The disclosure iscapable of other embodiments and of being practiced or being carried outin various ways.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “various embodiments,” “one or more embodiments” or “anembodiment” means that a particular feature, structure, material, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, the appearances of the phrases such as“in one or more embodiments,” “in certain embodiments,” “in variousembodiments,” “in one embodiment” or “in an embodiment” in variousplaces throughout this specification are not necessarily referring tothe same embodiment. Furthermore, the particular features, structures,materials, or characteristics may be combined in any suitable manner inone or more embodiments.

Reference will now be made to figures wherein like structures will beprovided with like reference designations. It is understood that thedrawings are diagrammatic and schematic representations of exemplaryembodiments, and are neither limiting nor necessarily drawn to scale.

The present disclosure relates to medical devices, systems and methodsfor enhancing visualization of an invasive procedure requiringprocedural guidance, such as providing enhanced visualization of avascular access device during an invasive insertion procedure. In one ormore embodiments, a catheter assembly is provided which includes acatheter adapter subassembly and a needle subassembly. The catheteradapter subassembly includes either a permanent magnet element ormagnetizable feature and the needle subassembly includes a permanentmagnet element or a magnetizable feature. Thus, in one embodiment, thecatheter adapter subassembly includes a permanent magnet and the needlesubassembly includes a magnetizable feature. In another embodiment, thecatheter adapter subassembly includes a magnetizable feature and theneedle subassembly includes a permanent magnet.

For clarity it is to be understood that the word ‘proximal” refers to adirection relatively closer to a clinician using the device to bedescribed herein, while the word “distal” refers to a directionrelatively further from the clinician. For example, the end of a needleplaced within the body of a patient is considered a distal end of theneedle, while the needle end remaining outside the body is a proximalend of the needle. “Magnetic feature” refers to a feature that includesa permanent magnet and/or a magnetizable material that has beenmagnetized by an externally applied magnetic field such that themagnetic feature can be detected by an ultrasound system. A“magnetizable feature” refers to an element that can become magnetizedand is detectable by an ultrasound system as described further herein.

Referring now to FIGS. 1-3, an exemplary embodiment of a catheterassembly 10 is shown, including a catheter adapter subassembly 12 and aneedle subassembly 14. The catheter adapter subassembly 12 comprises acatheter adapter 16, catheter tubing 18 and a securement element 22, andthe needle subassembly 14 further includes a needle 20, connected to aneedle hub 24, at a hub distal end 23 and a vent plug 26. In otherembodiments not shown, the needle 20 can be retracted into the needlehub 24 after the needle 20 has been used to prevent accidental needlesticks of a patient or a clinician.

Referring now to FIGS. 4 and 5, an embodiment of a medical device 100comprising a catheter assembly 110 is shown. The catheter assembly 110includes a catheter adapter subassembly 112 and a needle subassembly114. The catheter adapter subassembly 112 further includes a catheteradapter 116, catheter hub (not shown) and catheter tubing 118. Theneedle subassembly 114 further includes a needle 120, connected to aneedle hub (not shown), disposed within a needle hub 124 and a vent plug126. In the embodiment shown in FIGS. 4 and 5, the catheter adaptersubassembly 112 includes a permanent magnet element 132 and the needlesubassembly 114 includes a magnetizable feature 130, in particular onthe needle 120. According to an alternative embodiment (not shown), thisconfiguration is reversed wherein the permanent magnet element 132 is onthe needle subassembly 114, in particular on the needle 120, and themagnetizable feature 130 is on the catheter adapter subassembly 112.

The use of a permanent magnet element on the catheter adaptersubassembly 112 and a magnetizable feature on the needle subassembly 114provides the ability to calculate the catheter tip position and theneedle tip position based on known geometry relative to the position ofpermanent magnet element 132 on the catheter adapter subassembly 112from which a calculated catheter tip position and a calculated needletip position can be determined. The permanent magnet element 132provides a static magnetic field, while the magnetizable feature 130 onthe needle 120 can be magnetized with an externally applied magneticfield prior to insertion of the needle 120 into the patient.

In the embodiment shown in FIGS. 4 and 5, the magnetizable feature 130is on the needle 120, and the catheter adapter subassembly 112 includesthe permanent magnet element 132. The magnetizable feature 130 on theneedle 120 can be provided in a variety of ways. In one embodiment, theneedle 120 is made from a magnetizable material, for example, a steelmaterial that has a magnetic permeability that permits the needle 120 tobe magnetized by application of an external magnetic field. Stainlesssteel that is typically used to manufacture hypodermic needles formedical use, for example, type 304 stainless steel, may not have themagnetic permeability to be magnetized and used in a device accordingone or more embodiments. Type 304 stainless steel is an austenitic steelcomprising at least 18% chromium, 8% nickel, and a maximum of 0.08%carbon. Type 316 stainless steel is also used in the manufacture ofhypodermic needles, and type 316 stainless steel is also austenitic andnon-magnetic. The nickel content of type 316 stainless steel istypically higher than type 304 stainless steel, and type 316 stainlesssteel also includes the addition of molybdenum. According to one or moreembodiments, the needle 120 is made from martensitic or ferriticstainless steels, for example, type 420 or type 430 stainless steel.

In one or more embodiments, the magnetizable feature 130 on the needlecomprises a separate feature on the needle 120. Referring now to FIG.6A, in one embodiment, needle adhesive 140 is placed on a proximal end121 of the needle 120, which can be used to secure the needle 120 to thehub within the needle chamber 24. The needle adhesive 140 can be anysuitable adhesive such as a curable glue containing magnetizablenanoparticles such as magnetizable metal nanoparticles or magnetizablemetal oxide nanoparticles. The magnetizable metal can include iron,cobalt, nickel and alloys of iron, cobalt, and nickel. According to oneor more embodiments, the size of the magnetic nanoparticles is in therange of about 1 nanometer (nm) to about 100 nm. In one embodiment,adhesive is a light-curable glue, and in another embodiment, theadhesive is a heat-curable glue.

Referring now to FIG. 6B, an embodiment is shown in which themagnetizable feature is a needle ferrule 142 adjacent the distal tip 123of the needle 120. The needle ferrule 142 is made from a magnetizablemetal such as martensitic or ferritic stainless steels, for example,type 420 or type 430 stainless steel. The needle ferrule 142 provides atleast a localized area of increased outer diameter. As used herein, theterm “ferrule” refers to a separate member attached to the shank portionthe needle 120, providing at least a localized area of increased outerdiameter. The term “ferrule” includes a construction wherein the ferrulecomprises an integral part of the needle, defining a one-piecemonolithic construction composed of both the needle 120 and the needleferrule 142, as well as a construction in which the needle ferrule 142is a piece added to the needle by crimping the needle ferrule 142 ontothe shank of the needle 120.

Referring now to FIG. 6C, an embodiment is shown in which themagnetizable feature is a spot weld 144 adjacent the distal tip 123 ofthe needle 120. The spot weld 144 can be made from a magnetizable metalsuch as martensitic or ferritic stainless steels, for example, type 420or type 430 stainless steel.

Referring now to FIG. 6D, an embodiment is shown in which themagnetizable feature is a needle safety element, for example, a metalclip, specifically, a metal cannula safety clip 146 adjacent the distaltip 123 of the needle 120. The metal clip 146 can be made from amagnetizable metal such as martensitic or ferritic stainless steels, forexample, type 420 or type 430 stainless steel. In other embodiments, theneedle safety element can be embodied in other forms, for example, aspring, a plastic housing including a magnetizable feature, or othersuitable safety elements. According to one or more embodiments, thesafety element can be made from a materials that are not magnetic ormagnetizable and include a magnetizable or magnetic material.

Referring now to FIG. 6E, an embodiment is shown in which themagnetizable feature is a notch 148 in the needle 120, adjacent thedistal tip 123 of the needle 120. The notch 148 can include an insertmade from a magnetizable metal such as martensitic or ferritic stainlesssteels, for example, type 420 or type 430 stainless steel. The insertfits inside the notch 148 to completely or partially fill the notch 148.According to one or more embodiments, the insert can be a permanentmagnet, magnetic adhesive or other magnetic material. The notch can bepartially filled to occupy one-half the length of the notch 148.

Referring now to FIG. 7, an embodiment of a medical device 200comprising a catheter assembly 210 is shown. The catheter assembly 210includes a catheter adapter subassembly 212 and a needle subassembly214. The catheter adapter subassembly 212 includes a catheter adapter216, catheter hub (not shown) and catheter tubing 218, and the needlesubassembly 214 further includes a needle 220 connected to the needlehub 224, disposed within a needle hub 224 and a vent plug 226. In theembodiment shown in FIG. 7, the catheter adapter subassembly 212includes a permanent magnet element 232 and the needle subassembly 214includes a magnetizable feature 230, in particular on the needle 220. Inthe specific embodiment shown, the catheter adapter subassembly 212includes the catheter tubing 218 and a catheter adapter 216, and amagnetic adhesive 240 attaches the catheter tubing 218 to the catheteradapter 216. The magnetic adhesive 240 can be any suitable adhesive suchas a curable glue containing magnetizable nanoparticles such asmagnetizable metal nanoparticles or magnetizable metal oxidenanoparticles. The magnetizable metal can include iron, cobalt, nickeland alloys of iron, cobalt, and nickel. According to one or moreembodiments, the size of the magnetic nanoparticles is in the range ofabout 1 nanometer (nm) to about 100 nm. In one embodiment, adhesive is alight-curable glue, and in another embodiment, the adhesive is aheat-curable glue.

Referring now to FIGS. 8 and 9, an embodiment of a medical device 300comprising a catheter assembly 310 is shown. The catheter assembly 310includes a catheter adapter subassembly 312 and a needle subassembly314. The catheter adapter subassembly 312 includes a catheter adapter316, catheter hub (not shown) and catheter tubing 318, and the needlesubassembly 314 further includes a needle 320 connected to the needlehub 324, disposed within a needle chamber 324 and a vent plug 326. Inthe embodiment shown in FIGS. 8 and 9, the catheter adapter subassembly312 includes a magnetizable feature 330 and the needle subassembly 314includes a permanent magnet element 332.

FIGS. 10A-10D show various configurations for providing the magnetizablefeature 330 on the catheter adapter subassembly 312. In FIG. 10A, asecurement element in the form of a mandrel 342, which can be a conicalmandrel for connecting the catheter tubing 318 to the catheter adapter316, can be the magnetizable feature. According to one or moreembodiments, the mandrel 342 is includes or is manufactured frommartensitic or ferritic stainless steels, for example, type 420 or type430 stainless steel. It will be understood that in FIG. 10A, the mandrel342 is protruding from the catheter adapter 316. In other embodiments(not shown), the mandrel 342 can be recessed within the catheter adapter316.

In FIG. 10B, the securement element is shown in the form of a cathetertubing adhesive 340 is shown on the catheter tubing 318, which can beused to provide the magnetizable feature. The catheter tubing adhesive340 can be any suitable adhesive such as a curable glue containingmagnetizable nanoparticles such as magnetizable metal nanoparticles ormagnetizable metal oxide nanoparticles. The magnetizable metal caninclude iron, cobalt, nickel and alloys of iron, cobalt, and nickel.According to one or more embodiments, the size of the magneticnanoparticles is in the range of about 1 nanometer (nm) to about 100 nm.In one embodiment, adhesive is a light-curable glue, and in anotherembodiment, the adhesive is a heat-curable glue.

FIG. 10C shows an embodiment in which a blood control component 346shown exploded from the catheter adapter subassembly 312 to provide themagnetizable feature. In the embodiment shown, the blood controlcomponent is a spring that includes a magnetic element or magnetizablematerial. According to one or more embodiments, the blood controlcomponent 346 includes martensitic or ferritic stainless steels, forexample, type 420 or type 430 stainless steel. The blood controlcomponent (metal spring for instance) moves with the catheter adapteruntil fully advanced. It will be appreciated that in use the bloodcontrol component 346 in the form of a spring would be located withinthe catheter adapter 316, and may not be visible, unless the catheteradapter was made from transparent material.

FIG. 10D shows an embodiment in which a magnetic element 348 on thecatheter adapter 316 provides the magnetizable feature. According to oneor more embodiments, the magnetic element 348 is includes or is madefrom martensitic or ferritic stainless steels, for example, type 420 ortype 430 stainless steel. A magnetic wedge can provide a controlledposition on the catheter adapter subassembly 312 to provide a fixedmeasurement datum in a fixed location relative to the catheter distaltip and a wedge having a highly oriented grain structure due to the coldforming used during is fabrication is also beneficial in providing ameasurement datum. In one or more embodiments, the various alternativesdiscussed with respect to FIGS. 10A-10D may not have a position that isas precisely controlled. In one or more embodiments, the wedge, spring,and safety clip, would rely on catheter tip calculated projection ratherthan positional measurement.

In specific embodiments that include a magnetic adhesive, the adhesivecan include an additive selected from a paramagnetic additive, aferromagnetic additive and combinations thereof. The additive, accordingto one or more embodiments, includes a component selected from powderediron, magnetic iron oxide, magnetic titanium oxide, magnetic powderedsteel, and a magnetic iron alloy, and mixtures thereof. In specificembodiments, the magnetic iron alloy includes one or more of nickel,zinc, and copper. In specific embodiments, the additive furthercomprises a component selected from chromium, magnesium, molybdenum andcombinations thereof.

In one or more embodiments, the needle subassembly includes thepermanent magnet element, and the catheter adapter subassembly includesthe magnetizable feature, wherein the magnetizable feature includesmagnetizable catheter tubing. In one or more embodiments, at least aportion of the polyurethane tubing comprises a magnetizable compositionwhich is magnetizable by an externally applied magnetic field, themagnetizable composition comprising a magnetic material dispersed in thepolyurethane. In certain embodiments, the magnetic composition isdispersed in the polymeric material, for example, polyurethane, whichforms the tubing. In a specific embodiment, the magnetizable compositioncomprises an inner layer surrounding the lumen of the catheter with anouter layer of non-magnetizable polymeric material, for example,polyurethane. In an alternative specific embodiment, the layer ofmagnetizable composition is an outer layer surrounding an inner layer ofnon-magnetizable polyurethane. In one or more embodiments, themagnetizable composition forms longitudinal segments of the catheterseparated by longitudinal segments of non-magnetizable polymericmaterial, for example, polyurethane.

In any of the foregoing embodiments of the catheter, the magnetizablecomposition may further comprise a radiopaque component. Alternatively,in any of the foregoing embodiments, a non-magnetizable portion ofcatheter may comprise a radiopaque component

It will be understood that the permanent magnet element or a magnetizedmagnetizable feature for the embodiments described above, theorientation of the magnetic field can vary. The permanent magnet elementcan have north and south poles on axis with the catheter tubing and withthe needle. Alternatively, permanent magnet element or magnetizedmagnetizable feature can have north and south poles off axis with thecatheter tubing and with the needle, for example, the north and southpoles can be oriented perpendicular to the longitudinal axis of thecatheter tubing and the needle. For example, in FIG. 5, the magnetizablefeature 130 is shown as being magnetized with the north pole 130N andsouth pole 130S of the magnetizable feature 130 oriented parallel of thelongitudinal axis of the needle 120. The permanent magnet element 132associated with the catheter adapter subassembly 112 is shown with thenorth pole 132N and south pole 132S oriented perpendicular to thelongitudinal axis of the catheter tubing 118. In the configuration shownin FIG. 9, the permanent magnet element 332 and the magnetizable feature330, which has been magnetized, are shown with the poles 330N, 330S,332N and 332S oriented parallel to the longitudinal axis of the needle320 and the catheter tubing 318. Other variants are possible such as thepermanent magnet element and the magnetizable feature which has beenmagnetized having their north and south poles both orientedperpendicular or orthogonal to the longitudinal axis of the needle andthe catheter tubing.

An example of a vascular access device including a catheter according toany of the foregoing embodiments described above is illustrated in FIG.11. The vascular access device 500 shown in FIG. 11 comprises a catheteradapter subassembly 512 including a catheter adapter body 516 and acatheter tubing 518 and a permanent magnet element 532. A needle (notshown) within the catheter tubing includes magnetizable feature 530,which has been magnetized by application of an external magnetic fieldand can be any of the magnetizable features described herein.Magnetizing the magnetizable feature 530 with an externally appliedmagnetic field creates a magnetic field 515 in the region ofmagnetizable feature 530.

The vascular access device 500 may include a lateral access port 556 andmay be connected to a section of an extension tube 560 for establishingfluid communication between an IV fluid source and the catheter tubing518. In one or more embodiments, the extension tube 560 is built-in toreduce contamination and mechanical phlebitis by eliminatingmanipulation at the insertion site. In one or more embodiments, theextension tube 560 is compatible with high pressure injection. In one ormore embodiments, the extension tube 560 provides continuousconfirmation of vessel access during advancement of the catheter intothe patient vein.

In one or more embodiments, a needle 511 of a needle subassembly 514 isinserted into the lumen (not show) of the catheter tubing 518. Theneedle subassembly 514 is shown as including finger grips 584 positionedat the sides of the needle subassembly 514 to facilitate variousinsertion techniques. In one or more embodiments, bumps may be presenton the finger grip to indicate where to the user may grip the device forneedle removal. In one or more embodiments, a thumb pad 585, having agently convex surface, is provided at the proximal end of the needlesubassembly 514. A flange 586, having a gently convex surface, isprovided at the proximal end of the needle subassembly 514 to provide afinger pad. A wing member 570, thumb pad 585 and flange 586 may beutilized by the user during insertion, permitting the user to electwhich insertion technique to employ.

In one or more embodiments, the needle subassembly 514 includes a needleshield 580. The needle shield 580 may be a design adapted to secure thetip of the needle within the shield after use. In one or moreembodiments, the needle shield 580 may be activated passively. Theneedle tip is completely covered by the needle shield 580 in a fixedposition. In one or more embodiments, a ferrule, crimp or otherstructure may be included near the tip for engagement with a needleshield in certain applications.

A push tab 581 may be provided to facilitate catheter advancement duringinsertion. The push tab 581 also allows for one-handed or two-handedadvancement. In one or more embodiments, the push tab 581 is removedwith the needle shield 580. A clamp 582 may also be included on theextension tubing to prevent blood flow when replacing the access port.

In one or more embodiments, the vascular access device 500 furtherincludes a first luer access 572 and a second luer access 573 in fluidcommunication with the extension tube 560, a blood control split septum574 associated with the first luer access 572, and an air vent 576associated with the second luer access 573. Split septum 574 allows fora reduction in catheter-related bloodstream infection (CRBSI) whileproviding unrestricted flow and a straight fluid path and functions as ablood control septum. In one or more embodiments, the split septum 574may be located in an internal cavity of the catheter adapter or on thedistal end of the catheter adapter. In yet another embodiment, the splitseptum 574 may be located on a distal end of the extension tube 560. Theair vent 576 allows air to escape from the system during insertion,providing continuous confirmation of vascular access while preventingleakage of blood from the system during insertion. In one or moreembodiments, the air vent 576 may be at the distal end of extension tube560.

Another aspect of the disclosure pertains to a system for determiningcatheter tip location when the catheter tubing is inserted in a patient.According to one or more embodiments, a system provides a way toindependently measure the cannula tubing tip location by measuring thelocation and vector of the permanent magnet, and calculating andpredicting the catheter tip location relative to the position of themagnetic sensor(s) on an ultrasound probe and the ultrasound informationtransmitted from the sensors on the ultrasound probe. A permanent magneton a device with north and south poles on axis with the catheter andneedle and a known geometrical relationship to one or more featuresfixed on the catheter assembly provides a measurement datum that ismeasureable by the ultrasound probe magnetic sensors. From themeasurement datum based on the one or more features on the catheterassembly, the direction vector and position of the catheter tip, needletip or other features can be calculated. A magnetized magnetizableneedle or feature on the needle can then be used to independentlymeasure the position feature and calculate the position of the needletip. The calculated position of the needle tip or feature on the needlecan then be compared relative to the calculated position of the cathetertip to provide more specific information related to the catheterplacement process, such as needle and catheter tip position relative tothe patient's anatomy. This information can be used to determine (a) ifthe catheter is properly seated and ready for insertion (i.e., no overthe bevel condition), (b) when the needle tip is in the “hooded”position (needle tip just inside of the catheter tip), and (c) and (d)when the catheter is advanced to specific distances and at anglessuggesting successful placement in the vein.

Referring now to FIGS. 12A-D, an embodiment of a medical device 600comprising a catheter assembly 610 is shown. The catheter assembly 610includes a catheter adapter subassembly 612 and a needle subassembly614. The catheter subassembly 612 includes a catheter adapter 616,catheter hub (not shown) and catheter tubing 618 having a distalcatheter tip, and the needle subassembly 614 further includes a needle620 having a needle distal tip 623 connected to a needle hub 624, and avent plug 626. In the embodiment shown in FIGS. 12A-D, the catheteradapter subassembly 612 includes a permanent magnet element 632 and theneedle subassembly 614 includes a magnetizable feature 630. FIG. 12Bshows the catheter assembly 610 in 12A in when the needle distal tip 623is in the “hooded” position where the needle distal tip 623 is justinside of the catheter distal tip 619. Since the dimensions of thecomponents of the needle subassembly 614 are fixed and known, placementof the permanent magnet element 632 provides a known geometricalrelationship, for example, distance and angular position, with respectto one or more features fixed on the catheter assembly, which provides ameasurement datum 633.

Referring now to FIG. 12C, the catheter adapter subassembly 612 has beenadvanced in distal direction (toward the patient and away from theclinician), and the measurement datum 633 can be used to determine thedistance and angular movement of the needle 620 with respect to themeasurement datum 633. Similarly, if the catheter tubing 618 or otherpart of the catheter adapter subassembly 612 includes a magnetizablefeature, and the needle subassembly 614 includes a permanent magnet, thedistance and the angular movement of the catheter tubing 618 can bedetermined with respect to the measurement datum. FIG. 12C shows thatthe needle 620 has moved a distance D1, and the magnetizable feature 630has moved a distance D1 from the catheter distal tip 619. In FIG. 12D,the needle subassembly 614 has moved in a proximal direction (towardsthe clinician) for a distance D2, and the magnetizable feature 630 isnow at a distance D2 from the catheter distal tip 619. Each sequentialmovement of either a permanent magnet element or magnetized magnetizablefeature on a needle and/or the cannula can be measured and tracked usingan ultrasound system.

The location of the magnetized magnetic feature or permanent magnet on aneedle or cannula tubing can be accomplished by using a magnetometer todetermine the strength of the magnetic field and its direction. As usedherein, “magnetometer” refers to a device that detects a magnetic field.In specific embodiments, magnetometers may measure the strength of amagnetic field. When invasive needle or catheter is magnetic andproduces a known magnetic field B at a given distance x through tissueof permeability μ_(r), a mathematical correlation between the two i.e.x=f(B, μ_(r)) can be derived. In an embodiment, three differentmagnetometers are arranged in a three-dimensional grid array, orthogonalto each other, are used, and a three-dimensional (3D) correlation can bederived where I=f(B, μ_(r)) where i=x or y or z along three axes. Suchcorrelation can be extended to an array of 3-dimensional (3-D)magnetometers to obtain the precise distance to the magnetized catheteror vascular access device from the array of 3D magnetometers. If thelocation of the array of 3D magnetometers is known in reference to theultrasound sensor, then the precise location of the magnetized devicewith respect to the ultrasound sensor can be calculated. An inferredimage of the device can then be created and superimposed over theultrasound image and displayed. An exemplary magnetic sensing methodusing magnetometers and a lookup table instead of a mathematicalfunction to determine the location of a magnetized invasive device fromthe magnetic field strength measured outside the body usingmagnetometers is shown and described in United States Patent ApplicationPublication Number US20140257080 A1. The method described inUS20140257080 A1 can be adapted as described herein, for example, athree-dimensional (3D) correlation is from a mathematical function, andthe correlation is extended to an array of 3-dimensional (3-D)magnetometers, one of the magnetometers outside the patient's body, toobtain the precise distance to the magnetized catheter or vascularaccess device from the array of 3D magnetometers. Another exemplarymethod of referencing the magnetometers with respect to an ultrasoundprobe is described in PCT Patent Application Publication NumberW02013034175 A1, which can be adapted as described herein. For example,as shown in FIG. 13, an ultrasound system 700 is shown including acatheter adapter subassembly 712 comprising a magnetizable feature 732that has been magnetized as described herein is shown inside of apatient's body 800. It will be appreciated that the sizes shown are notto proportion and the sizes of the catheter adapter subassembly 712 andthe magnetizable feature 732 are exaggerated in size to illustrate theseelements more clearly. A magnetometric detector 711 comprising an arrayof magnetometers 720 (which can be housed in a probe of a ultrasoundsystem, not shown) arranged in a 3-D array can be used to sense themagnetic field 714 together with the terrestrial magnetic field and anyother background magnetic field. The magnetometric detector 711 is incommunication with an ultrasound processor 730 adapted to determine fromthe detected field the position and orientation of the magnetizablefeature 732 relative to the magnetometric detector 711. Thismagnetically detected position is then displayed on a display 750together with the ultrasound image.

The ultrasound system 700 can be a standard two dimensional B-modeultrasound system with a standard ultrasound probe modified by theprovision of the magnetometric detector 711. The ultrasound processor730, which can be connected to the ultrasound probe via a cable 735,sends electrical signals to the magnetometric detector 711 to cause itto generate ultrasound pulses and interpreting the raw data receivedfrom the transducer probe housing the magnetometric detector 711, whichrepresents echoes from the patient's body, to assemble it into an imageof the patient's tissue.

The magnetometric detector 711 can be attached to the ultrasound probeand can be battery powered or powered from the ultrasound system. Inspecific embodiments, positioning elements are provided on themagnetometric detector 711 to ensure that it is always attached in thesame well-defined position and orientation. The magnetometric detector711 can connected by a wireless connection to a base unit 740 which isin wireless or wired (e.g. USB) communication with the ultrasoundprocessor 730 and the display 750. The base unit 740 can be integratedwith, or some of its functions performed by, the ultrasound processor730 or the magnetometric detector 711.

The base unit 740 receives normalized measurements from magnetometricdetector 711 and calculates the position, or optionally the position andorientation, of magnetizable feature 732. The base unit 740 can alsoreceive additional information such as the state of charge of themagnetometric detector's battery and information can be sent from thebase unit 740 to the magnetometric detector 711, such as configurationinformation. The base unit 740 forwards the results of its calculations,i.e. the position and, optionally, orientation, to the ultrasoundprocessor 730 for inclusion in the displayed ultrasound image of animage of the catheter.

In one or more embodiments, the base unit 740 can be integrated into theultrasound system 700 with the ultrasound processor 730 and themagnetometric detector 711 being in direct communication with theultrasound system 700 either via wireless link or using the samephysical cable 735.

Thus, in one or more embodiments, the magnetizable feature is magnetizedusing any suitable device that can produce an magnetic field tomagnetize a needle or medical device to produce a magnetic field B at adistance x through tissue of permeability μ_(r), and the correlation iscalculated as x=f(B, μ_(r)). In one or more embodiments, threemagnetometers 720 are placed orthogonally to each other are used toderive a 3-dimensional correlation I=f(B_(i) , μ_(r)), wherein i=x or yor z along three axes. In a specific embodiment, the distance from themagnetizable feature to the 3-dimensional array of magnetometers iscalculated. In a further specific embodiment, location of the array ofmagnetometers in reference to an ultrasound sensor of an ultrasoundimaging system is used to calculate a location of the magnetizablefeature with respect to the ultrasound sensor. In another specificembodiment, the method comprises displaying an image of the magnetizablefeature.

As described above with respect to FIGS. 12A-D, providing a permanentmagnet on the needle subassembly and a magnetizable feature on thecatheter subassembly (or a reverse configuration in which themagnetizable feature is on the needle subassembly (e.g., the needle orneedle hub) and the permanent magnet is on the catheter subassembly)relative positions of a catheter tip and a needle cannula tip can bedetermined by utilizing an ultrasound system including a threedimensional array of magnetometers. Relative positional changes of thecatheter adapter subassembly and needle subassembly can be determined inthree axes, x, y and z, as well relative changes in angular motion w ofthe catheter adapter subassembly and the needle subassembly based onbased on a known geometrical relationship to one or more features fixedon the catheter adapter assembly or needle subassembly, which provides ameasurement datum that is measureable by the ultrasound probe magneticsensors. From the measurement datum based on the one or more features,the direction vector and position of the catheter tip or other featurescan be calculated based on a 3-dimensional correlation I=f(B_(i) ,μ_(r)), wherein i=x or y or z along three axes or predict relativemotion between the needle hub and catheter adapter subassemblies.Understanding the relative position and motion of these twosubassemblies can be used to inform a clinician of procedurallyimportant states of the insertion process, such as when the needle tipreaches the vein, when the catheter tip reaches the vein, when thecatheter is advanced to cover the needle tip (“hooding the catheter”)and thereby safe for further advancement.

Another aspect of the disclosure comprises methods that can be practicedaccording to any of the previously described systems. A method fordetermining a relative position of a catheter tip and a needle cannulatip, the method includes providing a catheter having a catheter distaltip and a needle having a needle distal tip, associating a permanentmagnet element with one of the catheter and the needle, associating amagnetizable feature with the other of the catheter and the needle,obtaining a measured position of the permanent magnet, obtaining ameasured position of the magnetizable feature to obtain a calculatedposition of the catheter distal tip, and comparing the calculatedposition of the catheter distal tip with the calculated position of theneedle distal tip to determine the relative position of the catheterdistal tip and the needle distal tip. In one embodiment, the needleincludes the magnetizable feature and the catheter includes thepermanent magnet and the relative position of the catheter distal tipand the needle distal tip indicates that the catheter is properly seatedon the needle. In another embodiment, the relative position of thecatheter distal tip and the needle distal tip indicates that thecatheter is in a hooded position on the needle. In another embodiment,the relative position of the catheter distal tip and the needle distaltip indicates that the catheter distal tip is advanced a specificdistance or angle.

In one embodiment of the method, the catheter adapter subassemblyincludes the magnetizable feature and the needle subassembly includesthe permanent magnet, and relative movement of the catheter adaptersubassembly and needle subassembly is determined by a three-dimensionalarray of magnetometers positioned in proximity to at least one of thepermanent magnet the magnetizable feature. In one embodiment of themethod, the method includes magnetizing the magnetizable feature byapplying an external magnetic field to the magnetizable feature. In oneembodiment, the three-dimensional array of magnetometers is part of anultrasound system, and the ultrasound system derives a three-dimensionalcorrelation to obtain a distance from the grid array to the magnetizablefeature or permanent magnet. In another embodiment, thethree-dimensional correlation is determined by the function I=f(B_(i) ,μ_(r)) , where i=x or y or z along three axes, x, y and z are distancesin three planes, B is a known magnetic field produced by the permanentmagnet or magnetizable feature, and μ_(r) is magnetic permeability.

In another embodiment of the method, the catheter adapter subassemblyincludes the permanent magnet and the needle subassembly includes themagnetizable feature, and relative movement of the catheter adaptersubassembly and needle subassembly is determined by a three-dimensionalarray of magnetometers positioned in proximity to at least one of thepermanent magnet the magnetizable feature. In one embodiment, the methodincludes magnetizing the magnetizable feature by applying an externalmagnetic field to the magnetizable feature. According to anotherembodiment, the three-dimensional array of magnetometers is part of anultrasound system, and the ultrasound system derives a three-dimensionalcorrelation to obtain a distance from the grid array to the magnetizablefeature or permanent magnet. In one embodiment, the three-dimensionalcorrelation is determined by the function I=f(B_(i) , μ_(r)), where i=xor y or z along three axes, x, y and z are distances in three planes, Bis a known magnetic field produced by the permanent magnet ormagnetizable feature, and μ_(r) is magnetic permeability.

Another aspect of the disclosure pertains to a catheter adaptersubassembly comprising a magnetic feature selected from the groupconsisting of a metal mandrel for connecting catheter tubing to the hub,a catheter tubing adhesive, a blood control component of the catheteradapter subassembly, and a magnetic wedge on the catheter adapter body.The catheter adapter subassembly may further comprise magnetic cathetertubing. According to an embodiment, the metal mandrel comprisesaustentitic stainless steel.

Although the disclosure herein provided a description with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thedisclosure. It will be apparent to those skilled in the art that variousmodifications and variations can be made to the devices, methods andsystems described in the of the present disclosure without departingfrom the spirit and scope thereof. Thus, it is intended that the presentdisclosure include modifications and variations that are within thescope of the appended claims and their equivalents.

What is claimed is:
 1. A medical device comprising: a catheter assembly,the catheter assembly including a catheter adapter subassembly and aneedle subassembly, wherein one of the catheter adapter subassembly andthe needle subassembly includes a permanent magnet element, and theother of the catheter subassembly and the needle subassembly includes amagnetizable feature.
 2. The medical device according to claim 1,wherein the needle subassembly includes the magnetizable feature and thecatheter adapter subassembly includes the permanent magnet element, andthe magnetizable feature of the needle subassembly is selected from thegroup consisting of a needle adhesive, the needle, a needle safetyelement, a notch, a needle ferrule, and a spot weld.
 3. The medicaldevice according to claim 1, wherein at least one of the permanentmagnet element and magnetizable feature includes an adhesive.
 4. Themedical device according to claim 3, wherein the catheter adaptersubassembly includes catheter tubing and a catheter adapter body, andthe adhesive attaches the catheter tubing to the catheter adapter body.5. The medical device according to claim 3, wherein the needlesubassembly includes a cannula and a hub, and the adhesive attaches thecannula to the hub.
 6. The medical device according to claim 1, whereinthe needle subassembly includes the magnetizable feature, a cannula anda hub, and the catheter adapter subassembly includes a catheter adapterbody, catheter tubing and the permanent magnet element, wherein thepermanent magnet element is selected from the group consisting of ametal mandrel for connecting catheter tubing to the hub, a cathetertubing adhesive, a blood control component of the catheter adaptersubassembly, and a magnetic wedge on the catheter adapter body.
 7. Themedical device according to claim 6, wherein the magnet on the catheteradapter body is integrally molded with the catheter adapter body.
 8. Themedical device according to claim 1, wherein the catheter adaptersubassembly includes the permanent magnet element and the needlesubassembly includes the magnetizable feature and the magnetizablefeature is a magnetizable needle.
 9. The medical device according toclaim 3, wherein the adhesive includes an additive selected from aparamagnetic additive, a ferromagnetic additive and combinationsthereof.
 10. The medical device according to claim 9, wherein theadditive includes a component selected from the group consisting ofpowdered iron, magnetic iron oxide, magnetic titanium oxide, magneticpowdered steel, and a magnetic iron alloy, and mixtures thereof.
 11. Themedical device according to claim 10, wherein the magnetic iron alloyincludes one or more of nickel, zinc, and copper.
 12. The medical deviceaccording to claim 10, wherein the additive further comprises acomponent selected from chromium, magnesium, molybdenum and combinationsthereof.
 13. The medical device according to claim 1, wherein the needlesubassembly includes the permanent magnet element, and the catheteradapter subassembly includes the magnetizable feature, wherein themagnetizable feature includes magnetizable catheter tubing.
 14. Themedical device according to claim 1, wherein needle subassembly includesa cannula, the catheter adapter subassembly includes a catheter adapterbody, catheter tubing and the permanent magnet element, and thepermanent magnet element has north and south poles on axis with thecatheter tubing and with the cannula.
 15. The medical device accordingto claim 1, wherein the needle subassembly includes a cannula and thepermanent magnet element, the catheter adapter subassembly includes acatheter adapter body and catheter tubing, and wherein the permanentmagnet element has north and south poles on axis with the cathetertubing and with the cannula.
 16. A system for determining relativeposition of a catheter adapter subassembly and a needle subassemblycomprising: a catheter having a catheter distal tip and a needle havinga needle distal tip; a permanent magnet element associated with one ofthe catheter adapter subassembly and needle subassembly; a magnetizablefeature associated with the other of the catheter adapter subassemblyand the needle subassembly; and magnetometers positioned with respect tothe catheter adapter subassembly and the needle subassembly, themagnetometers configured to determine relative movement of the catheteradapter subassembly and needle subassembly.
 17. The system of claim 16,wherein the permanent magnet or the magnetizable feature on a fixedlocation on the catheter adapter subassembly or needle subassemblyprovides a measurement datum to determine movement of the magnetizablefeature and permanent magnet.
 18. The system of claim 17, wherein thepermanent magnet is on the needle subassembly and the magnetizablefeature is on the catheter adapter subassembly.
 19. The system of claim17, wherein the permanent magnet is on the catheter adapter subassemblyand the magnetizable feature is on the needle subassembly.
 20. Thesystem of claim 17, wherein the magnetometers include three differentmagnetometers arranged in a three-dimensional grid array as part of anultrasound system which can derive a three-dimensional correlation toobtain a distance from the grid array to the magnetizable feature orpermanent magnet.
 21. The system of claim 20, wherein thethree-dimensional correlation is determined by a function I=f(B_(i)μ_(r)), where i =x or y or z along three axes, x, y and z are distancesin three planes, B is a known magnetic field produced by the permanentmagnet or magnetizable feature, and μ_(r) is magnetic permeability. 22.The system of claim 20, wherein the correlation provides a distance inthree planes to determine location of the catheter distal tip.
 23. Thesystem of claim 20, wherein the correlation provides a distance in threeplanes to determine location of the needle distal tip.
 24. A method fordetermining a relative position of a catheter tip and a needle cannulatip, the method comprising: providing a catheter adapter subassemblyincluding catheter and a needle subassembly including a needle, thecatheter having a catheter distal tip and the needle having a needledistal tip; associating a permanent magnet element with one of thecatheter and the needle; associating a magnetizable feature with theother of the catheter and the needle; obtaining a measured position ofthe permanent magnet; obtaining a measured position of the magnetizablefeature to obtain a calculated position of the catheter distal tip and acalculated position of the needle distal tip; and comparing thecalculated position of the catheter distal tip with the calculatedposition of the needle distal tip to determine the relative position ofthe catheter distal tip and the needle distal tip.
 25. The method ofclaim 24, wherein the needle includes the magnetizable feature and thecatheter includes the permanent magnet and the relative position of thecatheter distal tip and the needle distal tip indicates that thecatheter is properly seated on the needle.
 26. The method claim 24,wherein the relative position of the catheter distal tip and the needledistal tip indicates that the catheter is in a hooded position on theneedle.
 27. The method of claim 24, wherein the relative position of thecatheter distal tip and the needle distal tip indicates that thecatheter distal tip is advanced a specific distance or angle.
 28. Themethod of claim 24, wherein the catheter adapter subassembly includesthe magnetizable feature and the needle subassembly includes thepermanent magnet, and relative movement of the catheter adaptersubassembly and needle subassembly is determined by a three-dimensionalarray of magnetometers positioned in proximity to at least one of thepermanent magnet the magnetizable feature.
 29. The method of claim 28,further comprising magnetizing the magnetizable feature by applying anexternal magnetic field to the magnetizable feature.
 30. The method ofclaim 28, wherein the three-dimensional array of magnetometers is partof an ultrasound system, and the ultrasound system derives athree-dimensional correlation to obtain a distance from the array ofmagnetometers to the magnetizable feature or permanent magnet.
 31. Themethod of claim 30, wherein the three-dimensional correlation isdetermined by the function I=f(B_(i) μ_(r)), where i=x or y or z alongthree axes, x, y and z are distances in three planes, B is a knownmagnetic field produced by the permanent magnet or magnetizable feature,and μ_(r) is magnetic permeability.
 32. The method of claim 24, whereinthe catheter adapter subassembly includes the permanent magnet and theneedle subassembly includes the magnetizable feature, and relativemovement of the catheter adapter subassembly and needle subassembly isdetermined by a three-dimensional array of magnetometers positioned inproximity to at least one of the permanent magnet the magnetizablefeature.
 33. The method of claim 32, further comprising magnetizing themagnetizable feature by applying an external magnetic field to themagnetizable feature.
 34. The method of claim 32, wherein thethree-dimensional array of magnetometers is part of an ultrasoundsystem, and the ultrasound system derives a three-dimensionalcorrelation to obtain a distance from the array of magnetometers to themagnetizable feature or permanent magnet.
 35. The method of claim 34,wherein the three-dimensional correlation is determined by the functionI=f(B_(i) μ_(r)), where i=x or y or z along three axes, x, y and z aredistances in three planes, B is a known magnetic field produced by thepermanent magnet or magnetizable feature, and μ_(r) is magneticpermeability.
 36. A catheter adapter subassembly comprising a magneticfeature selected from the group consisting of a metal mandrel forconnecting catheter tubing to the hub, a catheter tubing adhesive, ablood control component of the catheter adapter subassembly, and amagnetic wedge on the catheter adapter body.
 37. The catheter adaptersubassembly according to claim 36, further comprising magnetic cathetertubing.
 38. The catheter adapter subassembly according to claim 36,wherein the metal mandrel comprises austentitic stainless steel.